1. Field of the Invention
The present invention relates to an apparatus and method for processing an edge of a glass sheet. More particularly, the present invention relates to an apparatus and method for cutting, scribing, grinding or polishing an edge of a glass sheet that can be used in a flat panel display.
2. Description of Related Art
Processing glass sheets that require a high quality surface finish like the ones used in flat panel displays, typically involves cutting the glass sheet into a desired shape and then grinding and/or polishing the edges of the cut glass sheet to remove any sharp corners. Today the grinding and polishing steps are usually carried out on an apparatus known as a double edger or double edging machine. Such double edging machines are known and available from Bando Kiko Co., Ltd., Mitsubishi Heavy Industries, Fukuyama Co., and Glass Machinery Engineering.
During the grinding and polishing of the edges of a glass sheet using a double edging machine, the glass sheet is typically sandwiched between two neoprene or rubber belts. The belts contact both surfaces of the glass sheet and cooperate to hold the glass sheet in place while the edges of the glass sheet are ground or polished by an abrasive grinding wheel. The belts also transport the glass sheet through a feeding section of the machine, a grinding or polishing section of the machine, and an end section of the machine.
This method of gripping, processing and conveying a glass sheet using a double edging machine has several disadvantages. First, the particles generated during edge finishing can be a major source of contamination on the surfaces of the glass sheet. Thus, the glass sheet requires extensive washing and drying at the end of the finishing process to clean and wash off the generated particles. Of course, the additional steps of washing and drying at the end of the finishing process impacts the original cost for the finishing line and increases the cost of manufacturing. Secondly, the particles and chips caught between the belts and the glass sheet can severely damage the surfaces of the glass sheet. Sometimes this damage can be the cause of a break source during subsequent processing steps and result in poor process yields due to a reduced number of selects that can be shipped to a customer.
To address these concerns, the surfaces of the glass sheet are currently protected by a plastic film to help prevent damage and contamination. But, if the source of contamination can be eliminated/minimized, then the plastic film is not needed and that would reduce the cost and complexity of the finishing process. Minimizing surface scratches would also help the glass manufacturer meet the customer's stringent demands and challenging specifications. Moreover, minimizing the generated particle levels would reduce the load on the washing equipment downstream. Accordingly, there is a need for an apparatus and method that helps prevent particles and other contaminants that are generated during edge finishing from contaminating or damaging the two surfaces of a glass sheet. This need and other needs are satisfied by the apparatus and method of the present invention.